Apparatus for feeding veneer to plywood assembly station

ABSTRACT

Apparatus for feeding veneer to a plywood assembly station is disclosed. The apparatus has three lift tables in line with the assembly station. The back lift table supports a supply of back veneer, the middle lift table supports a supply of face veneer, and the front lift table supports a supply of middle veneer. Two vertically stacked conveyors extend, respectively, from the outer two lift tables to lift tables to transport back veneer and face veneer, respectively, to an upper ready station. A third conveyor, below the other two conveyors, extends from the front lift table to transport middle veneer to a lower ready station. The back and face veneer are released together from the upper ready station to the assembly station, and the middle veneer is released alternately from the lower ready station to the assembly station.

United States Patent [72] Inventors Ronald ,I. Billett Sunnyvale; Donald W. C hamberlin, Los Gatos; Arthur L. McGee, San Jose, all of, Calif.

[21] Appl. No. 811,929

[22] Filed Apr. 1, 1969 [45] Patented 7 Sept. 7, 1971 [73] Assignee FMC Corporation San Jose, Calif.

[54] APPARATUS FOR FEEDING VENEER T0 PLYWOOD ASSEMBLY STATION 9 Claims, 18 Drawing Figs.

[52] 11.8. CI 214/85 R,

156/558, 156/563, 198/20, 198/79, 270/58' [51] lnt.Cl B65g 60/00 [50] Field of Search 214/85 A, 8.5 D, 8.5, 6 M;'l98/l59, 20 T, 79; 156/563; 270/58 [56] References Cited UNITED STATES PATENTS 591,801 10/1897 Agnew 214/6MUX 2,144,821 1/1939 Towmley 214/6 M X 3,327,872 6/1967 Madden 214/85 A CONVEYOR TO TAKE BACK VENEER TO UPPER READY DOLE LOWER READY STAT! 1 common TO TAKE MDDLE VENEER T0 LOWER READY STATION ASSEMBLY STATION, I5

3,404,789 10/1968 Georgeff 2l4/8.5D

Primary Examiner-Gerald M. Forlenza Assistant Examiner-George F. Abraham Attorneys-F. W. Anderson and C. E. Tripp ABSTRACT: Apparatus for feeding veneer to a plywood assembly station is disclosed. The apparatus has three lift tables in line with the assembly station. The back lift table supports a supply of back veneer, the middle lift table supports a supply of face veneer, and the front lift table supports a supply of middle veneer. Two vertically stacked conveyors extend, respectively, from the outer two lift tables to lift tables to transport back veneer and face veneer, respectively, to an upper ready station. A third conveyor, below the other two conveyors, extends from the front lift table to transport middle veneer to a lower ready station. The back and face veneer are released together from the upper ready station to the assembly station, and the middle veneer is released alternately from the lower ready station to the assembly station.

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REAR STATION VACUUM HEAD REAR STATlON LIFT TABLE ACTUATOR MIDDLE STATION VACUUM HEAD MIDDLE STATION LIFT TABLE ACTUATOR FRONT STATION VACUUM HEAD FRONT STATIION LIFT TABLE TUATOR APPARATUS FOR FEEDING VENEER TU IP'L'IIWOUIII ASSEMBLY STATION BACKGROUND OF THE INVENTION The present invention relates to apparatus for feeding veneer to a plywood assembly station.

Generally, plywood is assembled manually from veneer and glued core strips, the latter of which are sandwiched between the veneer to make up the plywood sheets, or panels. Normally, four operators are used to assemble each sheet: two operators to place veneer at an assembly station, one operator to pass core strips through a gluing machine, and one operator to take the glued core strip from the gluing machine and place them on the veneer. If, for example, five-ply plywood is being assembled, the first, third and fifth ply will be veneer; the second and fourth ply will be glued core strips. It is customary to use different quality veneer for the different plys which are made of veneer, the best quality veneer being used for the face veneer. Conventionally, the veneer handlers will bring the face veneer of one sheet and the back veneer of the next sheet together in stacked relation to the assembly station, since no glued core strips are required therebetween. The middle veneer is brought alone to the assembly station.

Efforts have been made to automate the plywood assembly process, but, in general, the mechanisms developed have been quite complicated and expensive. It will be appreciated that excessive complexity or high cost of the mechanism can render the device impractical or economically infeasible.

SUMMARY OF THE INVENTION In the present invention, simple, effective mechanism is provided for feeding veneer automatically up to an assembly station, eliminating the tiring manual transport of the veneer thereto. According to the present invention, veneer is automatically fed in coordinated relation from storage stations to ready stations adjacent the assembly station. In brief, in the preferred form of the invention, the veneer is piled on lift ta bles in three storage stations in line with the assembly station. The storage station for the back veneer is most remote from the assembly station; the storage station for the middle veneer is nearest the assembly station; and the storage station for the face veneer is between the other storage stations. A powerdriven conveyor leads from each storage station to the plywood assembly station. The three storage stations are positioned in a line, and the conveyors extend along that line in stacked relationship, the conveyor from the back storage station (at which the back veneer is stored) on top of the conveyor from the middle storage station (at which the face veneer is stored), and the conveyor from the middle storage station on top of the conveyor from the front storage station (at which the middle veneer is stored). The terminal portion of the conveyor from the middle storage station, and the conveyor from the from storage station, define ready stations to hold veneer until needed at the assembly station. Veneer from the top conveyor drops, one sheet at a time, into the upper ready station, and falls on top of a sheet of veneer on the intermediate conveyor. Thus, at the upper ready station, two sheets of veneer, which are held in the station by a stop until required in the assembly station, comprise the face veneer on the bottom and the back veneer on top. At the lower ready station, middle veneer is held until required in the assembly station.

It is, therefore, one object of the present invention to provide conveyors for automatically carrying veneer sheets in coordinated relation to an assembly station for forming plywood sheets. It is still another object of the present invention to feed veneer, of the type and quantity required, to a plywood assembly station, and to align sheets on one edge for correct placement for introduction to the assembly station.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic diagram showing movement of the veneer by apparatus of the present invention;

FIG. 2 is a view in perspective of an assembled plywood sheet, with layers of veneer broken away to show the construction of the sheet;

FIG. 3 is a view in perspective of the feed apparatus of the present invention and the assembly station which is supplied by said apparatus;

FIG. i is a side view, partly in cross section, of one of the front storage station for the middle veneer;

FIG. 5 is a view taken on the line 5--5 of FIG. 4;

IFIG. 6 is a view taken on the line 6-6 of FIG. 5;

FIG. '7 is a view taken on the line 77 of FIG. 6',

FIG. 8 is a side view, with parts broken away for clarity, of a stop to arrest the movement of veneer on a conveyor;

FIG. 9 is a side view showing the mounting on the frame of the bearing blocks for nip rollers which urge the veneer toward the assembly station;;

FIG. III is a schematic diagram showing drive elements for the feed apparatus of the present invention;

FIG. Ill is a schematic diagram showing the location of limit switches for controlling the apparatus of the present inven tion;

FIG. I2 is a schematic diagram of the pneumatic circuit for theapparatus of the present invention;

FIG. 13 is a schematic diagram of the hydraulic circuit of the present invention;

FIGS. M to I7 inclusive are schematic electrical circuit diagrams for apparatus of the present invention; and

IFIG. I8 is a schematic diagram of sequencing mechanism of the control system of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown in FIGS. I and 3 apparatus constructed in accordance with the present invention for feeding veneer to a plywood assembly station l5. Although many features of the present invention are applicable to manufacturing three-ply plywood sheets, the invention is shown for illustrative purposes as applied to processing fiveply sheets. In a typical plywood assembly station, the veneer and glued core strips are joined together to form the plywood sheet To shown in FIG. 2. Each plywood sheet is made up of back, or bottom, veneer Ida, a layer of cross core strips 17, middle veneer 16b, another layer of cross core strips 17, and face, or top, veneer Inc.

The apparatus of the present invention has a support frame ll ll at three veneer storage stations, two ready stations, and the conveyors therebetween. A rear, or back, storage station for the back veneer is indicated generally at Id. The rear storage station has a lift table, or elevator, IQ of the type shown in the US. Pat. No. 3,110,476 of W. A. Farris issued Nov. 12, I963. A table conveyor 19a, having rollers 19b, is mounted on the lift table to receive a stack of veneer introduced into the storage station from the side, as shown in FIG. 5. The lift table i9 is raised by a hydraulic actuator 26]! (FIG. I3) comprising cylinder Zll with a piston 22 therein. The piston is advanced to raise the table when motor HMTR is energized to operate the hydraulic pump Ill. The pump IIP draws hydraulic fluid from sump SU and delivers it under pressure through line 23 to cylinder 21 behind piston 22%. The table is lowered by energization of solenoid ll SOL of hydraulic lowering valve 24 to shift the valve spool 25 thereof to the right. As spool 25 shifts to the right, port 26 of the valve, which is connected to line 23, is unblocked for communication with discharge port 27, which is connected to discharge line 25. As fluid is released through valve 2 1i and discharge line 28, the piston 22 retracts under the weight of the table to permit the table to lower.

A middle storage station for the face veneer, indicated generally at 35, is positioned adjacent the rear storage station and toward the assembly station therefrom. The middle storage station has a lift table, or elevator, and table conveyor which is similar to the lift table and table conveyor of the rear storage station, and which is operated in the same manner. The parts of the middle storage station lift table and controls are identified by the same numerals as the rear storage station lift table and controls except that the solenoid which actuates valve spool is identified as 2 SOL and the motor which drives the pump is identified as 3MTR.

A front storage station for the middle veneer, indicated generally at 36, is positioned adjacent the middle storage station, in line with the middle and rear storage stations, but toward the assembly station therefrom. The front storage station has a lift table, or elevator, table conveyor, and controls similar to the other storage stations, which parts are identified by the same numerals as used for the other stations, except that the lowering valve solenoid is identified as SOL and the motor which drives the pump is identified as SMTR.

The lift table, or elevator, in each storage station is mounted on a stand, identified at 37 in the rear station, 38 in the middle station, and 39 in the front station. Stand 37 is higher than stand 38 which is higher than stand 39. Thus the aligned lift ta bles are progressively lower with the lowest table in the storage station nearest the assembly station which is aligned with the lift tables.

As shown in FIGS. 3 and 5, each storage station has an auxiliary storage conveyor, identified as 45 in the rear station, 46

in the middle station, and 47 in the front station. All of the auxiliary conveyors are of rectangular shape in plan as conveyor 47 although conveyors 45 and 46 are broken away in FIG. 3 for clarity. The height of the auxiliary storage conveyor at each storage station is equal to the height of the lift table conveyor at that station when the lift table is in its lowermost position as shown in FIG. 5. Each auxiliary storage conveyor has rotatable rollers 48' so that veneer stacked on the auxiliary conveyor of a storage station can be transferred onto the lift table conveyor of that storage station when the lift table is lowered. A stack of veneer is stored on the auxiliary conveyor of each storage station as the previous stack of veneer is being depleted in the storage station. Thus, when a stack in the storage station is depleted, the table is lowered and the stack on the auxiliary storage conveyor is immediately shifted onto the lift table so that operations can resume without delay.

Between the front storage station 36 and the assembly station, are two stacked roller conveyors, an upper conveyor 50 and a lower conveyor 51, as shown best in FIGS. 3 and 4. Each conveyor defines a ready station to hold veneer for selective release when needed in the assembly station. Each of the ready station conveyors 50, 51 have power driven rollers 52 which are turned slightly toward a side guide plate 49 to urge the veneer traveling toward the assembly station against the guide plate. Thus, sheets released from the ready stations will be properly aligned for introduction to the assembly station. The rollers 52 are driven by an endless belt 53, the upper run of which is engaged with the rollers 52 to impart rotation thereto. The belt 53 is mounted on a plurality of pulieys 43 joumaled in the frame. Each ready station 50, 51 has a gate at the downstream end thereof. As shown best in FIGS. 4 and 8, the upper conveyor 50 has gate Gd pivotally mounted on axis 54 and extending between side members of the conveyor frame 14. A pneumatic actuator 55 is mounted on the frame 14 and, as shown in FIG. 12, comprises cylinder 56 with a piston 57 slidably received therein. A piston rod 58 is connected, through link 59, with gate G4 to flip the gate down to the nonblocking position, when the piston and piston rod are retracted. The actuator 55 is controlled by a valve 60 which has a solenoid operated movable valve spool member 61 therein. When the solenoid 10 SOL of the valve is deenergized, the valve spool member is in the position shown, and compressed air from a source CA is supplied through line 62 to the pressure port 63 of the valve. The air passes through the valve to motor line 64 and into cylinder 56 behind the piston 57 thereof. Thus, in this position of the valve member, the piston rod 58 is extended and the gate G4 held up to block veneer. At this time, the cylinder in front of the piston is open to the atmosphere through motor line 65, valve 60, and discharge line 66 which has restriction 67 therein. Restriction 67 limits the flow of air through line 66 to control the speed of the actuator operation. When the solenoid 11 SOL of the valve is energized, the valve member thereof is shifted to the left of the position shown to direct compressed air entering pressure port 63 to motor line 65. In this latter position of the valve member, piston 57 and rod 58 are retracted to lower the gate and pass the veneer. Air from behind the piston escapes through line 64, valve 60 and discharge line 68 which has a restriction 69 therein to limit the speed of retraction of piston 57.

The lower ready station conveyor 51 has a similar gate, identified as G5, which is operated and controlled by an actuator 55 and valve 60 identical to the actuator and valve which controls gate G4, except that the valve member 61 is operated by a solenoid identified as 11 SOL.

As shown best in FIGS. 3, 4 and 10, the rear and middle storage stations 18 and 35 have, respectively, conveyors 75, 76 which lead from the storage stations to the upper ready station conveyor 50. The two conveyors 75, 76 lie in closely spaced stacked relation. The conveyor 75, which connects the rear storage station to the upper ready station, passes directly over the middle storage station and over the conveyor 76 which extends therefrom. Each of the conveyors 75, 76 have rollers 52 driven by an endless belt 53 mounted on pulleys 48 in the same manner as the rollers are driven in conveyors 50, 51. The rollers, as in conveyors 50, 51 are turned slightly to one side to guide the veneer against a side plate. Each conveyor 75, 76 has a gate, G2 and G3, respectively, at its downstream end. The upper conveyor 75 has, in addition, a gate G1 midway between the upstream and downstream ends of the conveyor. The gates G1, G2, and G3 are operated by the same type of actuator and valve as gates G4 and G5. Solenoids 5 SOL, 6 SOL, and 7 SOL, respectively, operate the valves 60 which control the gates G1, G2, and G3.

The endless belts 53 which drive the rollers 52 are driven as shown best in FIGS. 4 and 10. A motor SMTR is connected by chain 81 to a sprocket 82 which is connected to the pulley 48 at the upstream end of the conveyor 75. Conveyor 75 has two endless belts 53. Drive is transmitted from the upstream belt 53 to the downstream belt 53 through a chain 88 mounted on sprockets 83, 84 which are connected, respectively, to the inner end pulleys for the belts 53. Power is transmitted by chain 91 to the sprocket on the lower nip, or pinch, roller 92 which is normally engaged with, and rotates, upper pinch roll 92. A chain 95 transmits power to a sprocket 94 on brush 96 which sweeps the veneer as it emerges from the pinch rollers.

The drive system provided for the middle station conveyor 76 and the upper ready station conveyor 50 is similar to the drive system for conveyor 75. The drive motor, however, corresponding to motor SMTR is identified as motor 7MTR.

The drive system for ready station conveyor 51 has a motor 9 9MTR which drives through chain 102 a sprocket 101 connected to the upstream end pulley 48 of the conveyor. A chain 106 engaged with sprocket 101 drives the lower nip roller 107 through sprocket 103 on the roller, and the roller in turn, drives the upper nip roller 108. A chain 109 between the lower nip roll and a sprocket 104 on brush 1 10 provides power for the latter. Power is transmitted from sprocket 104 on brush 111) to sprocket on the lower nip roller 111 at the downstream end of conveyor 75 by chains 1 l2 and 113 which are connected in driving relation through a double idler sprocket unit 114. The lower nip roller 111 drives the upper nip roller 1 12.

In each pair of nip rollers, the upper roller thereof is journaled in a bearing block 115 (see FIG. 9) which is mounted on studs 116 received in a bracket 117 secured to the conveyor frame. The studs are threadedly received in the bracket and extend therethrough to receive the lower bearing block 118. Nuts 119 hold the block 118 securely to the bracket. Springs 12%) mounted on the studs between the heads thereof and the upper bearing block 115 urge that block toward the bracket. Each time a sheet of veneer is received between the nip rollers, the upper nip roller (and bearing block thereof) yields (against the force of the springs) to permit the veneer to pass between the rollers. If, however, two veneer sheets inadveranus ins tently cling together and are introduced between the rollers, the upper roller and bearing block are raised sufficiently to operate a limit switch mounted over the upper bearing block. Limit switch EELS is mounted at the upstream end of corn veyor 75 to detect removal of two sheets of baclt veneer from the rear storage station; limit switch ZliEllLS is mounted at the upstream end of conveyor 76 to detect removal of two sheets of face veneer from the middle storage station; and limit switch 3513 is mounted at the upstream end of conveyor hi to detect removal of two middle sheets from the front storage station.

Each storage station as a carriage T29 to shift veneer, one sheet at a time, from the top of the stack on the lift table to the conveyor.

As shown best in FIGS. 5, ti and '7 a track Tl is mounted to the frame on one side of each storage station, and a track T2 is mounted to the frame on the opposite side of each storage station. The carriage 129 has a hollow enclosed duct llflitl on which is mounted a fan housing ldl containing a fan (not shown). A motor is mounted on the fan housing at each storage station to drive the fan; motor ZMTR at the rear station; motor dMTR at the middle station; and motor llillMTlR at the front station. A beam 1132 is mounted on the duct, and pads 133 connected on an arm llZb extending therefrom ride in the track Tl. Similar pads mounted on the bracket liZld extending from the duct ride on track Til.

The carriage 129 is advanced and retracted by a pneumatic actuator ll35 having a cylinder 136 connected to the frame, as shown in FlGS. t3 and 13. The cylinder i136 has a piston l3? therein which is connected by connecting rod T38 and linlt l39 to beam 132. A control valve Mill has a movable valve member ll lll therein. Line 62, which is connected to the source of compressed air, is connected to the pressure inlet port 142 of the valve. When the solenoid of the valve is deenergized, and the movable valve member is in the position shown, pressure is introduced through motor line M3 to the cylinder 136 in front of the piston. The cylinder behind the piston is vented to atmosphere through motor line lid ll, valve i410, and discharge line Hi5 containing a restriction Mfr therein to adjust the retraction of the piston. When the valve solenoid is energized, the movable valve member Mt is shifted to the right to introduce compressed air through motor line Md to the cylinder behind the piston to advance the piston. Air in front of the piston is vented through motor line M3, valve Md, and discharge line t l-7 containing restriction Md therein to establish the speed of advance of the piston.

Each carriage duct has a bottom opening which is sur' rounded by skirt lull. W hen the fan motor is energized to drive the fan, air is evacuated from the duct to create a vacuum at the bottom opening thereof. Thus, the carriage duct defines a vacuum head which grips the top sheet of veneer on a stack on the lift table in the storage station when the table is raised to bring the top sheet into engagement with the skirt toil. Thereafter, when the control valve solenoid is energized to advance the piston i137 and connecting rod 13ft, the vacuum head is advanced to insert the top sheet from the stack into a funnel guide 16?. (H6. 5) at the downstream end of each of the storage stations. The funnel guide has converging top, bottom, and sides to guide a sheet between the nip rol lers and iron out wrinkles in the veneer at the upstream end of conveyors 75, 7b and 5t. Solenoid 3i SOL operates the solenoid valve Mil to control the rear storage station vacuum head; solenoid 4 SOL operates the solenoid valve ll ltl to control the middle storage station vacuum head; and solenoid Alli SOL operates the solenoid valve i l-li to control the front station vacuum head.

The electrical circuit for the apparatus of the present invention is shown in N65. lid, l5, l6, and 117. in the schematic diagram, the switch contacts of relays are given numbers cor responding to the limit switch by which they are operated. Normally open relay contacts are indicated by vertical parallel lines; normally closed relay contacts are indicated by vertical parallel lines with a diagonal therethrough. Normally open limit switch contacts are indicated by a weighted switch arm with the outer end below the contact point; normally closed limit switch contacts are indicated by a weighted switch arm with the outer end above the contact point. Lines which bridge drawing FlGURES are indicated by numbers Lil to L12 inclusive for convenience in following a line from one Figure to the next. Generally, there is no need to refer to these line numbers in the description which follows, and, accordingly, reference to most of these numbers is omitted in the description.

The location of the limit switches which control the operation of the feeding mechanism of the present invention is shown in FlG. ill. The limit switches llLS, 6L3, and lZLS are located in the back, middle, and front storage station, respectively, for engagement by the top sheets on the stacks. The limit switches are operated when the stacks are raised and are not released until the last sheet is taken from the stack. The limit switches 3L8, 8L5, and folds are also located in the back, middle, and front storage stations, respectively, a pair (identified by like numbers) in each station, for engagement by the top veneer on the stacks when the stacks have been lifted to their proper height for feeding and for disengagement by the top veneer when the stacks are depleted to a level too low to be gripped by the vacuum heads. The switches of each pair are spaced apart to sense the level of either side of the stack. Limit switches 2L5, 'TLS and 417LS are operated by the lift tables in the back, middle, and front, storage stations, respectively, when the lift tables are in their lowermost positions. Limit switch llllLS is operated by a sheet of veneer at gate Gil; limit switch ll'l'LS is operated by a sheet at gate G2; limit switch llEllLS i5 is operated by a sheet at gate G3; limit switch ants is operated by a sheet at gate G4; and limit switch lliLS is operated by a sheet at gate G5. Limit switch ZllLS is operated by a sheet passing through gate G2.

in addition to the limit switches shown on FIG. ll, limit switch EELS, ZElLS, and 35L? are located over the bearing bloclcs (Fit). 9) for the nip rollers at the back storage station, the middle storage station, and the front storage station, respectively, for operation by the blocks in the event that more than one sheet at a time passes through the rollers. Limit switches EELS, MLS, 271.8, and 28143 are operated in sequence by cams of a timer T (FIG. lid). Photocells PC2 and M33 are located at gates G2 and G3 to detect veneer sheets of substandard width.

The depression of pushbutton switch APB (FIG. M) closes contacts il Bll thereof to energize relay 1C and close normally open contacts MIT and 1C2; thereof. With contacts lCll closed, relay it: will remain energized until stop push button switch is depressed to open contacts SPBl thereof. When contacts 1C2 close, lines Lil and L2; are connected across source S, and the circuitry connected across those lines is ready for operation.

Assuming the back table is down and loaded with veneer, limit switch 215 is operated to hold open normally closed contacts ELSE thereof. When pushbutton switch ESPB is depressed to close contacts dPBt thereof, relay Milk is energized to close normally open contacts ilClRll, to close normally open con tacts liCliIll, and to open normally closed contacts tClRB. At this time, limit switch llLS, which is operated by the presence of the top sheet of veneer when. the lift table is up, is unoperated and the switch arm of contacts llLSi assume their normal up position, bridging contacts llLSla, lLSlb. Thus, relay MIR is sealed in through contacts 6PB2, iLSll and llCltll. The two limit switches 3L5, which sense the height of the veneer stack on the back table, have normally open contacts Zllhiill and normally closed contacts ELSZ. initially, the staclt height switches EELS are not operated, and contacts FiLSfil are closed to energize relay lll/l. When relay TM is energized, normally open contacts ill/ill are closed to energize electric motor The energiza'tion of motor illvlTR raises the back storage station lift table, lFiG. i3, until the stack height limit switches 3L3 are operated when the stack is at the proper height for feeding. During the stack elevation, limit switch lLS is operated to close contacts ILSIa and ILSlc, dropping out the coil of relay lCR, bypassing 1CR2 contacts. At this time, relay 2M is energized through contacts ILSI to close contacts 2M1 and energize electric motor 2MTR which runs the fan to create a vacuum in the back vacuum head. The table continues to rise until either of the 3LS limit switches operate to deenergize motor lMTR and stop the elevation of the stack. When the stack height limit switches 3LS are operated, contacts 3LS1 are closed and contacts 3LS2 are open. This energizes lamp 2LT to indicate the stack of back veneer is ready for feeding.

A similar circuit is provided to control the middle table which carries the face veneer. Assuming the middle table is down and loaded with veneer, limit switch 7LS is operated to hold open normally closed contacts 7LSI thereof. When pushbutton switch SP8 is depressed to close contacts 5PB2 thereof, relay 2CR is energized to close normally open contacts 2CRI, to close normally open contacts 2CR2, and to open normally closed contacts 2CR3. At this time, limit switch 6L8, which is operated by the presence of the top sheet of veneer when the lift table is up, is unoperated and the switch arm of contacts 6LS1 assume their normal up position, bridging contacts 6LS1a, 6LS1b. Thus, relay 2CR is sealed in through contacts 7PB2, 6LS1, and 2CR1. The two limit switches 8LS, which sense the height of the veneer stack on the middle table, have normally open contacts 8LS1 and normally closed contacts 8LS2. Initially, the stack height switches 8LS are not operated, and contacts 8LS2 are closed to energize relay 3M. When relay 3M is energized, normally open contacts 3M1 are closed to energize electric motor 3MTR. The energization of motor 3MTR raises the middle storage station lift table, FIG. 13, until the stack height limit switches 8LS are operated when the stack is at the proper height for feeding. During the stack elevation, limit switch 6LS is operated to close contacts 6LSIa and 6LSlc, dropping out the coil of relay 2CR, bypassing 2CR2 contacts. At this time, relay 4M is energized to close contacts 4M1 and energize electric motor 4MTR which runs the fan to create a vacuum in the middle vacuum head. The table continues to rise until either of the SL8 limit switches operate to deenergize motor SMITR and stop the elevation of the stack. When the stack height limit switches 8LS are operated, contacts 8LSI are closed and contacts 8LS2 are open. This energizes lamp 3LT to indicate the stack of face veneer is ready for feeding.

A similar control circuit is associated with the front table on which the middle veneer is stacked. Assuming the front table is down and loaded with veneer, limit switch 47LS is operated to hold open normally closed contacts 47LS1 thereof. When pushbutton switch SP3 is depressed to close contacts 5PB3 thereof, relay 80CR is energized to close normally open contacts 80CR1, to close normally open contacts 80CR2 (FIG. and to open normally closed contacts 80CR3. At this time, limit switch 12LS, which is operated by the presence of the top sheet of veneer when the lift table is up, is unoperated and the switch arm of contacts 12LS1 assume their normal up position, bridging contacts l2LS1a, 12LS1b. Thus, relay 80CR is sealed in through contacts 40PB2, IZLSI, and 80CR1. The two limit switches 16LS, which sense the height of the veneer stack on the back table, have normally open contacts 16LS1 and normally closed contacts 16LS2. Initially, the stack height switches 16LS are not operated, and contacts 16LS2 are closed to energize relay 8M. When relay SM is energized, normally open contacts 8M1 are closed to energize electric motor 8MTR. The energization of motor SMTR raises the front storage station lift table, FIG. 13, until the stack height limit switches 16LS are operated when the stack is at the proper height for feeding. During the stack elevation, limit switch 12LS is operated to close contacts 12LS1a and IZLSIc, dropping out the coil of relay 80CR, bypassing 80CR2 contacts. At this time, relay 10M is energized to close contacts 10M]. and energize electric motor llIlMTR which runs the fan to create a vacuum in the front vacuum head. The table continues to rise until either of the 16LS limit switches operate to deenergize motor 8MTR and stop the elevation of the stack. When the stack height limit switches 16LS are operated, contacts 16LS1 are closed and contacts I6LS2 are open. This energizes lamp 30LT to indicate the stack of middle veneer is ready for feeding.

At this time, then, all the stacks are up ready for feeding veneer to the assembly station In order to prepare the system for feeding, the conveyors are next started. Push button switch 9P8 is depressed, closing contacts 9PB1, 9PB2, and 9PB3 to energize, respectively, relays 5M, 7M, and 9M. Normally open contacts 5M2 close to seal in relay 5M. Normally open contacts 5M1 close when relay SM is energized to energize the back table conveyor electric motor SMTR; normally open contacts 7M1 close when relay 7M is energized to energize the middle table conveyor motor 7MTR; and normally open contacts 9M1 close when relay 9M is energized to energize the front table conveyor motor 9MTR (see FIG. 10). With no sheet at gate G1, limit switch L8 is unoperated and normally closed contacts llLSI thereof are closed; thus, solenoid 3 SOL is energized. Solenoid 3 SOL, when energized, effects advance of the back table vacuum head (see FIG. 12) to insert a sheet of veneer into funnel guide 162 and between the nip rollers of conveyor 75, thus starting a sheet of back veneer toward the assembly station.

The switch arm of contacts 17LS1 normally bridges contacts l7LSla and l7LSlc, and when there is no sheet at gate G2 to operate limit switch 17LS, solenoid 5 SOL is energized since normally open contacts 2M2 of relay 2M and normally closed contacts 11CR1 are closed at this time. The energiza tion of solenoid 5 SOL effects opening of gate G1 (see FIG. 12) to permit the sheet of back veneer to pass to gate G2, which is closed at this time. With a sheet at gate G2, limit switch 17LS is operated, causing the switch arm at contacts 17LSI to bridge contacts 17LSla and l7LSlb. The contacts 17LS1a, 17LS1c open to deenergize solenoid 5 SOL and cause gate G1 to close.

Since there is, again, no sheet at gate G1, limit switch contacts lILSl close to again energize solenoid 3 SOL and feed another back sheet to conveyor 75. With the first back sheet at gate G2, gate G1 remains closed to hold the second back sheet at gate G l.

The switch arm of limit switch contacts 13LS1 normally bridges contacts 13LS1a and 13Ls1c. Thus, when contacts 7M2 close on energization of relay 7M, solenoid 4 SOL is energized to actuate the middle table vacuum head feed (see FIG. 12) and shift the top sheet of face veneer to the middle table conveyor 76. When the sheet reaches gate G3, limit switch 13LS is operated, causing the switch arm at contacts 13LS to bridge contacts l3LSa and l3LSlb. The contacts 13LS la, 12LSlc open to deenergize solenoid 4 SOL.

When relay 9M was energized, normally open contacts 9M2 thereof closed to seal in the relay. With no no sheet at gate G5 at this time, normally closed limit switch contacts 41LS1 are closed and the solenoid 41 SOL is energized to actuate the front table vacuum head feed (see FIG. 12). Thus, the top sheet of middle veneer from the front table is fed to the front table conveyor 51 and is stopped thereon by gate G5. At this time, then, there is a sheet of back veneer at gate G1; a sheet of back veneer at gate G2; a sheet of face veneer at gate G3; a sheet of middle veneer at gate G5; and no sheet at gate G4.

At this time, selector switch 188 (FIGS. 16 and 17) is placed in the manual position (down), closing contacts 1881 and 1882 thereof. When contacts 1SS1 are closed, solenoid 6 SOL is energized through normally closed counter contacts CTR2, normally closed contacts CTR], normally open contacts 4CR1, and normally open (now closed) contacts 20LS3, to open gate G2 (see FIG. 12), thereby passing a sheet of back veneer to gate G4. With no sheet at gate G2, limit switch contacts ll7LSlla and 17LS1c (FIG. 15) again close, energizing solenoid 5 SOL to open gate G1 and pass a sheet of back veneer from gate G1 to gate G2. As the sheet arrives at gate G2, limit switch 17LS is again operated to deenergize solenoid 5 SOL and close gate Gll. With no sheet at gate G1, limit switch llLS is released to close normally closed limit switch contacts llLSll and energize solenoid 3 SOL. The energization of solenoid 3 SOL actuates the back table vacuum head to introduce to the back table conveyor 75 another sheet of back veneer which stops at gate Gll. Thus, now, there is a sheet of back veneer at each of the gates Gll, G2, and G4; a sheet of face veneer at gate G3; and a sheet of middle veneer at gate G5.

A stepping switch ST (FIG. 17) has every other contact connected to line Li, and a relay l2CR is connected between the switch arm STA and line L2. The switch arm is actuated by energization of the coil STC of the switch ST to move from one contact to the next. Thus, when the switch arm is on every other contact, the normally open contacts ll2CRll and ll2CR2 are open and the normally closed contacts 112CR3 and l2CR4 (FIG. T6) are closed. When the switch arm is on alternate contacts, the normally open contacts II2CRl and 12CR2 are closed and the normally closed contacts ll2CR3 and lIZCRd are openv When contacts 1852 (FIG. 17) of selector switch 155 close, and normally closed contacts lllCRll are closed, the stepper coil STC will be energized if, and only if, the switch arm STA is on one of the contacts which energize relay II2CR to close the normally open contacts of the switch. If this is the case, the switch arm will be stepped to deenergize relay TZCR. if the switch arm is on a contact which does not energize relay l2CR, the stepping coil STC is not actuated. Thus, regardless of the contact on which the arm initially rested, the relay IZCR will be, or become, deenergized at this time.

At this time the selector switch 135 is put in the automatic position (up) to close contacts 1583 and 1854 (FIG. 16) thereof. To start the automatic cycle, push button switch 25PB is depressed to energize the cycle timer motor lllllVlTlR (see FIG. 18). The motor is connected to a gear reducer GR which has an output shaft OS on which cams CA1, CA2, CA3 and CA 1- are mounted. Each cam is in registration with the actuating arm of one of the limit switches 25LS, 26LS 27LS, and 28LS. As soon as the output shaft turns, cam CA ll actuates the arm of limit switch 28LS to close the normally open contacts 2M5] thereof(FlG. I16) and seal in the motor TTMTR for one complete cycle, at which time the contacts 2LSl open to stop the motor llllMlTR.

At the same time the motor illlli/ITR becomes energized, relay 7CR is picked up through normally closed contacts SCRl and normally closed contacts 7CRll. Relay 7CR is sealed in through the normally closed contacts 25LS1 of limit switch ZSLS (FIG. MB). and normally open contacts 7CRll. At this time, then, solenoid it) SOL is energized through normally closed contacts TZCR T and normally closed contacts dCRll as normally open contacts 7CR2 close. Energization of solenoid ltl SOL opens gate Gd (FlG. I12) and releases a baclc sheet loa to the plywood assembly station.

After a predetermined lapse of time, during which the men at the assembly station. 15 lay a layer of glued core strips 17 on the back sheet Ida, the limit switch 27LS is operated by cam CA3 (FIG. llfl). Thus, normally open contacts ZILSll (FlG. 16) close to energize relays SCR, 9CR and lldClit. The relays SCR, 9CR and llllCF. are sealed in through normally open contacts 9Cl-1ll and normally closed limit switch contacts 2v6LSll. When relay iiCR is energized, contacts hCRll open to prevent premature reenergization of 7CR relay on the subsequent cycle.

After a second lapse of time while the baclt sheet is being fed through gate G4, the cycle timer motor llllMTR causes limit switch 25LS to be actuated. Normally closed contacts 25LSI open to deenergize relay 'ICR. Gate Gd then closes. With the absence of the back sheet at gate G4, limit switch ZllLS is released to cause gate G3 to open by energizing solenoid 7 SOL and relay MCR thru 201.82 normally closed contacts, normally open contacts 4M2, and normally closed con tacts 3CFt2. When relay 3CIR is energized because of a narrow sheet, solenoid 7 SOL can be energized through normally open contacts dCRZ. With the face sheet leaving gate G3,

ll ll l4lCR2 normally open contacts close in the circuit counter circuit CTR to register a single count toward a predetermined number of sheets of assembled plywood. Contacts MCRI FIG. l5 close to monitor a photo electric cell circuit, which determines if the sheet passing is of acceptable or substandard width. In the latter event, an alarm circuit is energized.

The previous face sheet leaving gate G3 arrives at gate G4 to operate limit switch 20LS, causing normally open limit switch contacts 201.83 to close in the circuit to energize solenoid 6 SOL and cause the release of a back sheet through gate G2 onto the now placed face sheet. (From now until the predetermined count is reached in counter CTR from signals through contacts MCRZ, a pair of face and back sheets will be fed on each cycle through gate G4). As the next face sheet arrives at gate G3, through a sequence of previously described events, limit switch 113LS is actuated causing time delay relay llTD (FIG. 15) to be energized, starting a short delay interval to close gate G2 through the opening of delay open contacts lTlDT and the resultant deenergization of relay 4CR. Normally open lCRl contacts (FIG, no open to deenergize solenoid 6 SOL. However, if the delay interval is less than the time required for the sheet to pass gate G2, normally open limit switch 2lLSll contacts will cause solenoid 6 SOL to remain energized for the demand.

In the assembly station, the sheet fed through gate G4 continues to advance and be worked on. The cycle timer causes the limit switch 26LS to be actuated to deenergize relays SCR, QCR and ltlCR. Also limit switch ZEILS is actuated by cam CA4 to stop the cycle timer motor IITMTR.

To build a five ply sheet, alternate operation of gate 4 and gate 5 must be initiated. As previously described, the operation of selector switch ISS prepares this operation for its proper sequence. At the conclusion of each cycle of the cycle timer motor llllMTR, limit switch 2fi lLS is operated by cam CA2 to close normally open contacts 26LS2 (FIG. 17) and energize the stepper coil STC of stepper switch ST to move the switch arm STA thereof to the next contact, thereby ener gizing relay T2CR. Thus, normally open contacts l2CRl and TZCRZ close and normally closed contacts TZCRS and IIZCRA open. As limit switch 26LS is operated, contacts 26LSl open to drop relays hClR, SCR, and llliCR (FIG. 16). When the camshaft OS driven by motor llllMTR completes one revolution, limit switch MLS is released to open contacts ZliLSll thereof and deenergize the motor El lllViTR At this time, the cir cuit is conditioned for release of another sheet of veneer to the assembly station. When pushbutton switch ZSFB is again pushed, the timer T (FIG. 18) initiates another cycle, and 7CR is again energized. Therefore, solenoid llllSOL (FIG. 17) is energized through normally open contacts 7CR3 and contacts l2ClPt2 to open gate G5 (see FIG. l2) and release a sheet of middle veneer to the assembly station. Thereafter, the operators at the assembly station lay a layer of glued core strips on the middle sheet of veneer.

As the operators lay the glued core sheets on the sheet of middle veneer, the apparatus goes through another cycle, bringing veneer to the gates where required.

When the operators at the assembly station are ready for the face sheet (and the back sheet of the next piece of plywood which is released with the face sheet of the previous plywood piece), pushbutton 25PB is again depressed to energize the motor llllt/ITR, which is sealed in by the normally open contacts 253L511 as the camshaft begins to rotate and operate limit switch ZSLS. At the same time, relay 'ICR is picked up and sealed in. When relay 'ICR is energized, solenoid Ill} SOL is energized through contacts 7CR2 of the relay to open gate G 5 and release the top and bottom veneer therein.

The two stacked sheets of veneer, with the top sheet on the bottom are deposited on the glued core strips to complete one piece of plywood and provide the bottom piece for the next sheet of plywood.

When a predetermined number of sheets of plywood have been assembled (as determined by the number of sheets passing gate G3), contacts CTRII (FIIG. 17) close to energize a signal lamp 4LT through normally open contacts CR1 which are closed each cycle.

The operation of limit switch 25LS by cam CA1 opens contacts 25LS1 (FlG. 16) to release relay 7CR. When normally open contacts 7CR2 of relay 7CR open, solenoid 10 SOL is deenergized to close gate G4. At the same time, normally open contacts 25LS2 (FlG. 17) close, permitting relay 11CR, to energize through now closed CTRl and 10CR1 contacts, and be sealed in by normally open contacts 11CR2. When relay llCR is energized, contacts 11CR3 thereof close to energize solenoid 6 SOL after normally closed contacts LS1 close as the pair of sheets leaves gate G4. The energization of solenoid 6 SOL opens gate G2 (FIG. 12) to deposit a sheet of back veneer at gate G4. It will be noted that solenoid 6 SOL, which operates gate G2, is held in through normally open contacts 21LS1 of limit switch 21LS. Limit switch 21LS is operated by a sheet passing through gate G2 and is released, to drop 6 SOL and close gate G2, when the sheet is completely through gate G2. As the sheet leaves gate G2, gate G1 is opened, as previously described, to feed another sheet to gate G2. A new sheet is then supplied to gate G1 as previously described. As relay 11CR is energized, normally open contacts 11CR4 thereof close to energize a signal A83, through normally open contacts 10CR3, to indicate that the desired count has been reached. Normally closed contacts 10CR4 prevent the alarm from being sounded before relay 11CR is energized.

When the supply of veneer on the back table is depleted, pushbutton switch 6PB (FIG. 14) is depressed, closing contacts 6PB1 and opening contacts 6PB2. Opening of contacts 6PB2 disables relays ICR, 1M, 2M, and lamp 2LT. The closing of contacts 6PB1 energizes solenoid 1 SOL through normally closed contacts 1CR3 and 2LS1. The energization of solenoid 1 SOL lowers the back lift table (see FIG. 13). Contacts 2LS1 will remain closed until the table operates limit switch 2LS as it reaches the lower limit of its travel, at which time contacts 2LS1 open to drop solenoid l SOL. Similarly, when the middle table is empty, operation of pushbutton switch 7PB will close contacts 7PB1 and open contacts 7PB2 thereof. Opening contacts 7PB2 will disable relays 2CR, 3M, 4M, and lamp 3LT. Closing contacts 7PB1 will energize solenoid 2SOL through normally closed contacts 2CR3 and normally closed contacts 7LS1. The energization of solenoid 2SOL lowers the middle lift table (see FIG. 13). Contacts 7LSl will remain closed until the table operates limit switch 7LS as it reaches the lower limit of travel, at which time contacts 7LS1 open to drop solenoid 2SOL. In a like manner, when the front lift table is empty, push button switch 40PB is depressed to close contacts 40PB1 and open contacts 40PB2. Opening contacts 40PB2 disables relays 80CR, 8M, 10M, and lamp 30LT. The closing of contacts 40PB1 energizes solenoid 45 SOL through normally closed contacts 80CR3 and normally closed contacts 47LS1. The energization of solenoid 45 SOL lowers the front lift table (P16. 13). Contacts 47LS1 will remain closed until the table operates limit switch 47LS as it reaches the lower limit of its travel, at which time contacts 47LS] will open to drop solenoid 45 SOL.

Two detector circuits lSW and 2SW are connected across lines L1, L2 to produce a warning signal when a sheet of substandard width is at gate G2 or gate G3. When photocell PC2 or PC3, which are positioned at the edge of a sheet of normal width at gates G2 and G3, respectively, is not operated by a sheet at those gates because the sheet is not wide enough to shield the photocell lens from the light, normally open contacts 1SW1 or normally open contacts 2SW1 close, depending on whether the narrow sheet is at gate G2 or gate G3. Relay 14CR is energized to close normally open contacts 14CR1 the same time solenoid 7 SOL is energized to open gate G3. Therefore, whenever a narrow sheet passes through gate G3, relays 3CR and SCR are energized. When relay 3CR is energized, normally open contacts 3CR1 thereof (FIG. 17) close and, since normally open contacts 14CR3 are closed at the time, alarm bell ABl rings. The energization of relay SCR opens normally closed contacts SCRI (FIG. 17) to disable the counter CTR and prevent registration of a count as the narrow sheet passes through gate G3. When a sheet is at gate G2, the switch arm of contacts "L5 is raised to bridge contacts 17LSla and 17LS1c (H6. 15). Relay 13CR (FIG. 16) is energized to close normally open contacts 13CRl the same time solenoid 6 SOL is energized to open gate G2. Therefore, whenever a narrow sheet passes through gate G2, relay 6CR is energized. When relay 6CR is energized to close normally open contacts 6CR1 (FIG. 17), alarm bell A82 is energized since normally open contacts 13CR2 are closed at the time. Alarm bells A51 and A82, when energized, are sealed in through contacts 3CR1 and 6CR1, respectively, and contacts 30PB1 of alarm reset pushbutton 30PB. When pushbutton 30PB is depressed to release alarm bells ABl, AB2, solenoid 6 SOL is momentarily energized, when there is a narrow sheet at gate G4, to open gate G2 and replace the narrow sheet which is removed by the operator.

When more than one sheet of veneer is introduced inadvertently by the back, middle, or front vacuum head to the nip rollers, limit switch 22LS, 23LS, or 3SLS will be operated, to close either normally open contacts 22LS1, 23LS1, or 35LS1 (FIG. 16). When any of these contacts close, the alarm horn AH is connected across lines L1, L2 to sound an alarm.

Pushbutton switch 49PB, having two normally closed contacts 49PB1 (FIG. 16), 49PB2 (FIG. 17), and normally open contacts 49PB3, 49PB4 is provided to reset the counter CTR.

In the operation of the apparatus of the present invention, veneer is fed alternately from the upper ready station 50 and the lower ready station 51 to the plywood assembly station 15: the veneer from the upper ready station comprising a face sheet 16c and a back sheet 16a released as a unit with the face sheet on the bottom, and the veneer from the lower ready station comprising a single sheet of middle veneer 161).

Sheets of veneer are supplied alternately from the back, or rear, station conveyor 75 and from the middle station conveyor 76 to the upper ready station. Veneer from the front storage station is fed directly to the lower ready station 51.

Sheets of veneer are fed from the storage stations 18, 35, and 36 to the conveyors and ready station by a movable vacuum head 129.

The control of the series of gates G1, G2, G3, G4, and G5, and the control of the vacuum heads in the storage stations, coordinates the flow of veneer from the storage stations to the assembly station. Sheets are automatically moved downstream, from gate to gate, as required, for ultimate release to the assembly station. The assembly station may be similar to the assembly station shown and described in the copending patent application of Billett and Viitanen entitled APPARATUS FOR ASSEMBLING VENEER INTO PLYWOOD SHEETS filed Apr. 1, l969, Ser. No. 813,812, and assigned to the same assignee as the present invention.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

1 claim:

1. In a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a first storage station for back veneer, a second storage station for face veneer, and a third storage station for middle veneer, a first ready station for face and back veneer, a second ready station for middle veneer, means to transfer back veneer from said first storage station to said first ready station, means to transfer face veneer from said second storage station to said first ready station, means to transfer middle veneer from said third storage station to said second ready station, and means to transfer veneer from said ready stations to said assembly station.

2. The machine of claim 1 including means selectively to control the transfer of veneer from said ready stations to feed the veneer alternately from said first ready station and from said second ready station.

3. The machine of claim 1 in which said first and second ready stations are positioned in stacked relationship.

4. The machine of claim 3 in which said means to transfer veneer to said first ready station constitutes stacked conveyors leading, respectively, from said first storage station and said second storage station.

5. The apparatus of claim 1 in which said storage stations are aligned with the assembly station and in which said first storage station is most remote from the assembly station and said third storage station is closest to the assembly station.

6. The apparatus of claim 5 in which said ready stations are in stacked relation with said first ready station on top of said second ready station.

7. In a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a plurality of storage stations for veneer of different quality, said storage stations aligned with said assembly station, a plurality of conveyors to receive veneer from said storage stations, said conveyors arrayed in stacked relation and extending respectively from said storage stations toward said assembly station, a plurality of ready stations, said ready stations mounted in stacked relation adjacent the assembly station and each ready station positioned to receive veneer from a particular conveyor, at least one of said ready stations positioned to receive lid veneer from more than one of said conveyors, means to control the flow of veneer from each storage station to each ready station, and means to control the release of veneer from the ready stations to the assembly station.

8. in a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a first storage station for back veneer, a second storage station for face veneer, and a third storage station for middle veneer, a plurality of ready stations to receive the veneer, means to transfer back veneer from said first storage station to one of said ready stations, means to transfer face veneer from said second storage station to one of said ready stations, means to transfer middle veneer from said third storage station to one of said ready stations, and means to release the face and back veneer substantially simultaneously to the assembly station and to release the middle veneer sequentially to said substantially simultaneous release of the face and back veneer.

9. ln plywood layup apparatus having an assembly station, the combination comprising, a plurality of storage stations for plywood veneer, power driven conveyors extending between said storage stations and said assembly station to deliver the veneer to the assembly station, and an auxiliary storage station adjacent each of said storage stations.

f Abstract, line 7, delete "to lift tables my I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 3, 3 Dated September 7, 1971 Inventor(s) RONALD J, BILLETT, DONALD W, CHAMBERLIN, and

ARTHUR L, MDGEE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1, line 65, after "provide" insert simple, effective,

mechanism for moving plywood veneer to a plywood assembly station. It is another object of the present invention to provide Col. 5, line 72, after "corresponding" insert to the relays by which they are actuated, and limit switch contacts are given numbers corresponding Col. 8, line 52, change "lELSlc" to l3LSlc Col. 8, line 5 delete (first occurrence) "no" Signed and sealed this 6th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTISCHALK Attesting Officer Commissioner of Patents 

1. In a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a first storage station for back veneer, a second storage station for face veneer, and a third storage station for middle veneer, a first ready station for face and back veneer, a second ready station for middle veneer, means to transfer back veneer from said first storage station to said first ready station, means to transfer face veneer from said second storage station to said first ready station, means to transfer middle veneer from said third storage station to said second ready station, and means to transfer veneer from said ready stations to said assembly station.
 2. The machine of claim 1 including means selectively to control the transfer of veneer from said ready stations to feed the veneer alternately from said first ready station and from said second ready station.
 3. The machine of claim 1 in which said first and second ready stations are positioned in stacked relationship.
 4. The machine of claim 3 in which said means to transfer veneer to said first ready station constitutes stacked conveyors leading, respectively, from said first storage station and said second storage station.
 5. The apparatus of claim 1 in which said storage stations are aligned with the assembly station and in which said first storage station is most remote from the assembly station and said third storage station is closest to the assembly station.
 6. The apparatus of claim 5 in which said ready stations are in stacked relation with said first ready station on top of said second ready station.
 7. In a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a plurality of storage stations for veneer of different quality, said storage stations aligned with said assembly station, a plurality of conveyors to receive veneer from said storage stations, said conveyors arrayed in stacked relation and extending respectively from said storage stations toward said assembly station, a plurality of ready stations, said ready stations mounted in stacked relation adjacent the assembly station and each ready station positioned to receive veneer from a particular conveyor, at least one of said ready stations positioned to receive veneer from more than one of said conveyors, means to control the flow of veneer from each storage station to each ready station, and means to control the release of veneer from the ready stations to the assembly station.
 8. In a machine to assemble plywood veneer in an assembly station to form a plywood sheet, the combination comprising a first storage station for back veneer, a second storage station for face veneer, and a third storage station for middle veneer, a plurality of ready stations to receive the veneer, means to transfer back veneer from said first storage station to one of said ready stations, means to transfer face veneer from said second storage station to one of said ready stations, means to transfer middle veneer from said third storage station to one of said ready stations, and means to release the face and back veneer substantially simultaneously to the assembly station and to release the middle veneer sequentially to said substantially simultaneous release of the face and Back veneer.
 9. In plywood layup apparatus having an assembly station, the combination comprising, a plurality of storage stations for plywood veneer, power driven conveyors extending between said storage stations and said assembly station to deliver the veneer to the assembly station, and an auxiliary storage station adjacent each of said storage stations. 